• Preventive Nutrition and Food Science
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• 제13권2호
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• pp.61-65
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• 2008

To evaluate the effect of ground cherry extract on the activity of aniline hydroxylase, we gave ground cherry extract in doses of 100, 200 or 400 mg/kg i.p to mice for 1, 2 or 4 days. The aniline hydroxylase activity in the group treated with ground cherry extract increased in a dose dependant manner in all experimental groups compared with the control group, and was significantly higher in the group treated with ground cherry extract at a dose of 200 mg/kg, which also exhibited a time dependant increase over 4 days. Enzyzme kinetic analysis was performed for hepatic aniline hydroxylase activity in the group treated with 200 mg/kg for 4 days. There was no change of the Km values for aniline hydroxylase between the experimental group and the control group, but the Vmax values for aniline hydroxylase was 21% lower in the experimental group compared with the control. The experimental group also showed lower lipid peroxide and reduced glutathione content, and there were no significant difference in serum alanine aminotransferase activity between the experimental group and the control. Aniline was injected into both the experimental group mice treated with ground cherry extract at a dose of 200 mg/kg for 4 days and the control group, and then the level of blood aniline was assayed at 1hr. The level of blood aniline was lower in the experimental than the control group. This study suggests that ground cherry extract induces hepatic aniline hydroxylase activity and might accelerate the scavenging system of reactive oxygen species. It is likely that ground cherry extract influences the metabolism of xenobiotics by activating AH activity substituted for CYP2E1.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.105-105
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• 2009

$ZrO_2$ is one of the most attractive high dielectric constant (high-k) materials. As integrated circuit device dimensions continue to be scaled down, high-k materials have been studied more to resolve the problems for replacing the EY31conventional $SiO_2$. $ZrO_2$ has many favorable properties as a high dielectric constant (k= 20~25), wide band gap (5~7 eV) as well as a close thermal expansion coefficient with Si that results in good thermal stability of the $ZrO_2/Si$ structure. In order to get fine-line patterns, plasma etching has been studied more in the fabrication of ultra large-scale integrated circuits. The relation between the etch characteristics of high-k dielectric materials and plasma properties is required to be studied more to match standard processing procedure with low damaged removal process. Due to the easy control of ion energy and flux, low ownership and simple structure of the inductively coupled plasma (ICP), we chose it for high-density plasma in our study. And the $BCl_3$ included in the gas due to the effective extraction of oxygen in the form of $BCl_xO_y$ compound In this study, the surface kinetic properties of $ZrO_2$ thin film was investigated in function of Ch addition to $BCl_3/Ar$ gas mixture ratio, RF power and DC-bias power based on substrate temperature. The figure 1 showed the etch rate of $ZrO_2$ thin film as function of gas mixing ratio of $Cl_2/BCl_3/Ar$ dependent on temperature. The chemical state of film was investigated using x-ray photoelectron spectroscopy (XPS). The characteristics of the plasma were estimated using optical emission spectroscopy (OES). Auger electron spectroscopy (AES) was used for elemental analysis of etched surface.

• 한국산학기술학회논문지
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• 제10권1호
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• pp.25-31
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• 2009

공기스프링을 감쇠기로 사용하는 방진대는 넓은 주파수대역에서 우수한 진동 절연성능을 가짐으로 널리 사용되어 왔다. 하지만 공기스프링은 구조적으로 저강성, 저감쇠의 특성을 가지고 있으므로 외란에 의해 쉽게 가진되어 안정성이 떨어지는 문제가 있다. 이에 공기스프링과 같은 수동소자만을 이용한 수동제어 형식의 보완을 위해 능동 및 반능동 방식의 감쇠기가 제안되고 연구되고 있다. 따라서 본 연구에서는 이러한 수동형 제진대의 능동 및 반능동제어를 위한 동역학적 해석에 관하여 연구하였다. 제진대의 제어시스템 구현을 위하여 6 자유도 제진대의 물리적인 특성에 기초한 동역학적 모델을 정립하고 해석 및 실험을 통해 동역학 모델의 적용가능성을 검증하였다.

• 한국전자통신학회논문지
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• 제9권9호
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• pp.1019-1025
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• 2014

최근 무인항공기(UAV : Unmanned Aerial Vehicle)에 대한 연구가 다양한 각도로 진행되어 군사용 비행체에 관한 연구에서 부터 민간용 비행체 및 일반 취미 활동용 비행체에 이르기까지 다양하게 연구가 진행되고 있다. 특히, 무인 소형 비행체에 대한 연구는 수직이착륙(VTOL : Vertical Take-Off and Landing)과 용이한 방향전환 및 정지비행(hovering)에 대하여 연구되고 있으며, 이러한 연구부분에 적합한 무인 소형 비행체가 쿼드로터(quardrotor)형 무인비행체를 중심으로 연구되고 있다. 이러한 무인 비행체에 대한 연구는 공기역학적 힘에 의해 부양되므로 복잡한 동역학 분석과정을 필요로 하고 있으며, 이러한 역학적 분석 및 실험적 모델을 바탕으로 제어기를 설계하고 있다. 본 논문에서는 일반적인 PID 제어기를 바탕으로 기본적인 자세제어를 구현한 후, 제어기 설계에 고려하지 못한 비선형적인 요소를 신경회로망(neural networks)의 강화학습(reinforcement learning) 알고리즘을 이용하여 일반적인 제어기 설계에 고려하지 못한 비선형적인 요소를 보완하여 보다 안정적인 쿼드로터의 자세제어 방안을 제시하고자 한다.

• International Journal of Vascular Biomedical Engineering
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• 제2권2호
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• pp.16-26
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• 2004

The object of this study is to develop a mathematical model of the hemodialysis system including the mechanism of solute kinetics, water exchange and also cardiovascular dynamics. The cardiovascular system model used in this study simulates the short-term transient and steady-state hemodynamic responses such as hypotension and disequilibrium syndrome (which are main complications to hemodialysis patients) during hemodialysis. It consists of a 12 lumped-parameter representation of the cardiovascular circulation connected to set-point models of the arterial baroreflexes, a kinetic model (hemodialysis system model) with 3 compartmental body fluids and 2 compartmental solutes. We formulate mathematically this model in terms of an electric analog model. All resistors and most capacitors are assumed to be linear. The control mechanisms are mediated by the information detected from arterial pressoreceptors, and they work on systemic arterial resistance, heart rate, and systemic venous unstressed volume. The hemodialysis model includes the dynamics of urea, creatinine, sodium and potassium in the intracellular and extracellular pools as well as fluid balance equations for the intracellular, interstitial, and plasma volumes. Model parameters are largely based on literature values. We have presented the results on the simulations performed by changing some model parameters with respect to their basal values. In each case, the percentage changes of each compartmental pressure, heart rate (HR), total systemic resistance (TSR), ventricular compliance, zero pressure filling volume and solute concentration profiles are represented during hemodialysis.

• Nuclear Engineering and Technology
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• 제11권2호
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• pp.111-117
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• 1979

Time of flight Technique를 사용한 coincidence spectrometer에 의해 액체 형광물질(liquid scintillator) NE213의 전자와 양자에 대한 빛 방출량을 측정하였다. 이 실험에서 양자에너지 (3.2Mev, 4Mev, 5Mev, 6Mev)는 2Mev에서 9Mev에 이르는 여러 에너지 분포를 갖고 있는 Am.Be 중성자원을 사용하여 중성자 탄성산란의 각도(45$^{\circ}$ and 60$^{\circ}$)와 측정기간의 거리를 조절하므로서 얻었다. NE213액체발광물질의 빛 방출량은 전자 에너지에 대해 선형적인 응답을 보였으며 양자에 대한 응답은 에너지 증가에 따라 비선형적이었다. 빛의 세기도 전자에 의한 응답이 양자에 의한 것보다 약 세배 가랑 컸다. 본 실험결과는 Batchelor et at 이 발표한 실험결과와 거의 비슷했다.

• 한국미생물·생명공학회지
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• 제22권1호
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• pp.85-91
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• 1994

The characteristcs of monascus fermentation using a hyperpigment-producing mutant, Monascus sp. J101, were analyzed, and the extractive fermentations employing permeabilizing agents and resin were carried out to increase the productivity of red pigment. And the kinetic analysis was also carried out in case of the monascus fermentation using Amberlite XAD-7. The extracellular content of the red pigment produced by Monascus sp. J101 was about 17% of the total, and the production of pigment was regulated by its own product. The cell growth reached a stationary phase at 48 hours ofter inoculation, whereas the pigment production continued up to 100 hours, which showed the pattern of a mixed growth-associated type. During the fermentation, various permeabilizing agents were added to the culture medium and their effects on pigment production were examined. By adding 0.05% Triton X-100 at 48 hours of cultivation, about an 18% increase in pigment production was accomplished as compared to the control, 12% ethyle acetate and 15% for 0.05% deoxycholate, respectively. When a nonionic adsorbent, Amberlite XAD-7 was added to the culture medium at a concentration of 12.0% at 48 hours of cultivation, the pigment production was enhanced by about 48.9% as compared to the control.

• BMB Reports
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• 제32권1호
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• pp.67-71
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• 1999

We have investigated the effect of cholestasis on the closely related acyl-CoA:amino acid N-acyltransferase, benzoyltransferase, and phenylacetyltransferase activities in rat liver. Benzoyltransferase and phenylacetyltransferase activities in the liver cytosol, mitochondria, and microsome were investigated for a period of 42 d after common bile duct ligation. Both the mitochondrial and microsomal benzoyltransferases showed significant increase in their activities between the 1st and 7th day after common bile duct ligation, although the cytosolic benzoyltransferase activity did not show a significant change compared to the activities from the sham-operated control. The cytosolic phenylacetyltransferase activity showed a significant increase between the 1st and 2nd day, the mitochondrial activity showed a significant increase between the 2nd and 7th day, and microsomal activity showed a significant increase between the 1st and 7th day, respectively. Enzyme kinetic parameters of hepatic benzoyltransferase were analyzed using benzoyl coenzyme A as a substrate with the preparations from the 1st day post-ligation. Enzyme parameters of hepatic phenylacetyltransferase were also analyzed using phenylacetyl coenzyme A as a substrate with the preparations from the 2nd day post-ligation. The results indicated that although the $K_m$ values of these enzymes were about the same as the sham-operated control, the $V_{max}$ values of both enzymes increased significantly. These results, therefore, suggest that the biosynthesis of benzoyltransferase and phenylacetyltransferase has been induced in response to cholestasis.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.819-822
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• 2002

It is necessary for the numerical simulation of 3-dimensional incompressible isotropic decaying turbulence to construct 3-dimensional initial velocity field which resembles the fully developed turbulence. Although the previous velocity field generation method proposed by Rogallo(1981) satisfies continuity equation and 3-dimensional energy spectrum, it has limitation, as indicated in his paper, that it does not produce the higher velocity moments(e. g. velocity derivative skewness) characteristic of real turbulence. In this study, a new velocity field generation method which is able to control velocity derivative skewness of initial velocity field is proposed. Brief descriptions of the new method and a few parameters which is used to control velocity derivative skewness are given. A large eddy simulation(LES) of isotropic decaying turbulence using dynamic subgrid-scale model is carried out to evaluate the performance of the initial velocity field generated by the new method. It was shown that the resolved turbulent kinetic energy decay curve and the resolved enstrophy decay curve from the initial field of new method were more realistic than those from the initial field of Rogallo's method. It was found that the dynamic model coefficient from the former was initially half the stationary value and experienced relatively short transition period, though that from the latter was initially zero and experienced relatively longer transition period.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.479-482
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• 2002

Riblets with longitudinal grooves along the streamwise direction have been used as an effective flow control technique for drag reduction. A flexible micro-riblet with v-grooves of peak-to-peak spacing of $300{\mu}m$ was made using a MEMS fabrication process of PDMS replica. The flexible micro-riblet was attached on the whole surface of a NACA0012 airfoil with which grooves are aligned with the streamwise direction. The riblet surface reduces drag coefficient about $7.9{\%}\;at\;U_o=3.3m/s$, however, it increases drag about $8{\%}\;at\;U_o=7.0m/s$, compared with the smooth airfoil without riblets. The near wake has been investigated experimentally far the cases of drag reduction ($U_o\;=\;3.3 m/s$) and drag increase ($U_o\;=\;7 m/s$). Five hundred instantaneous velocity fields were measured for each experimental condition using the cross-correlation PIV velocity field measurement technique. The instantaneous velocity fields were ensemble averaged to get spatial distribution of turbulent statistics such as turbulent kinetic energy. The experimental results were compared with those of a smooth airfoil under the same flow condition. The micro-riblet surface influences the near wake flow structure largely, especially in the region near the body surface